1. Field of the Invention
The present invention is related generally to integrated circuits, and more specifically to a contact between different layers of polycrystalline silicon interconnect.
2. Description of the Prior Art
In semiconductor circuits, it is known that ohmic contacts are desirable between interconnect layers. An ohmic contact is one in which no P-N junction is formed.
When polycrystalline silicon interconnect lines having different conductivity types make contact, a P-N junction is formed. A similar junction can be formed when polycrystalline silicon having the same conductivity type, but very different doping levels (such as N.sup.-- to N.sup.+) make contact. For various reasons, it is often desirable to have interconnect having different conductivity types make contact, and it would be desirable to provide an ohmic contact for such structures.